I had to look up Heidi Montag, as I vaguely recognized the name, but had no idea who she was. Reality TV stars are, generally, among the most ephemeral of celebrities, save for the very few who managed to leverage it into something bigger. So, I don't find it surprising at all when their fifteen minutes of fame evaporate.

A lot of the people who were celebrities when I was growing up aren't in the public eye any more, largely because they're dead or retired.